C语言练习题（二）

1、编程实现strcpy，要求不要调用库函数，注意函数入口参数检查。（25分）；

char *my_strcpy(char *dest,char *str1)

{

char *temp=dest;

while(*str1!='\0')

{

*temp=*str1;

temp++;

str1++;

}

*temp='\0';

return dest;

}

2、用读写操作等实现“cp”功能。（25分）；

#include <stdio.h> #include <stdlib.h> #include <string.h>

int main() { FILE *from_fptr; FILE *to_fptr; char ch; if((from_fptr = fopen("a.c","r+")) == NULL) { printf("cannot open file,strilk any key exit!\n"); exit(0); } if((to_fptr = fopen("b.c","w+")) == NULL) { printf("cannot open file,strilk any key exit!\n"); exit(0); } while((ch = fgetc(from_fptr)) != EOF) { fputc(ch,to_fptr); } fclose(from_fptr); fclose(to_fptr);  return 0; }